Technical Field
This application relates to a method for eliminating electromagnetic interference (EMI), and in particular, to a device and a method for eliminating EMI.
Related Art
Electronic products may generate electromagnetic radiation during operation, and electromagnetic radiation may interfere with normal operation of other devices or even affect human health. Therefore, most countries all draw up rules for electromagnetic radiation of electronic products to prevent EMI from bringing harm.
As one of components of an electronic product, an “integrated circuit (IC)” is one of primary sources of electromagnetic radiation. Electromagnetic radiation generated by an “inductor” in the IC may interfere with an external device and may also interfere with operation of internal components on some applications. Particularly, in an inductor-capacitor tank (LC tank) in a differential mode, if equivalent inductances of inductors at positive and negative ends are mutually asymmetric, a common-mode signal appears at a junction of the inductors at the positive and negative ends, and the common-mode signal exists on a metal wire electrically connected to the junction and causes electromagnetic radiation.
Currently, a common manner is using a power output end plus an EMI suppression component or using an RC (a resistor and a capacitor are connected in series) buffer circuit. However, the EMI suppression component can weaken only a part of conducted interference and cannot weaken radiated interference. The RC buffer circuit can have certain effects on a low-power circuit but is generally ineffective to a high-power circuit.